Machine-to-machine communications (Machine-to-Machine Communications, M2M) is a network-based application and service with intelligent interaction between machines as a core, and implements data communication without manual intervention by embedding a wireless or wired communications module and application processing logic into machines, so as to satisfy an information requirement of users in aspects such as monitoring, commanding and scheduling, data collection, measurement.
In addition, a completely new globalization standards organization oneM2M is set up. An overall objective of the oneM2M is to create an open standard for a service layer of M2M communications, to facilitate establishing a future network that integrates various devices and services, so that M2M services are interoperable, and M2M applications can invoke an infrastructure service and can be implemented independent of a network.
Referring to FIG. 1, FIG. 1 is an architectural diagram of M2M in the prior art.
An application entity (Application Entity, AE) on an M2M device communicates with a common services entity (Common Services Entity CSE) on an M2M device by using a reference point X; in a standard of the oneM2M, common services entities (Common Services Entity CSE) communicate with each other by using a reference point Y; the common services entity CSE communicates with an underlying network function unit (Underlying Network Function, NSF) by using a reference point Z.
Currently, M2M communications may be based on a wired manner or a wireless manner, where the wireless manner includes a cellular network and a short range communications manner, and a 3GPP cellular network is widely used.
Referring to FIG. 2, FIG. 2 is a schematic structural diagram of the oneM2M in the prior art, which defines components included in a CSE, where functions of a data management and storage unit (Data Management & Repository, DMR) are as follows:                collecting data;        performing data analysis and collation;        helping data invoking between CSEs and applications;        aggregating data; and        searching for data.        
Refer to FIG. 3, which is a network topology diagram of supported deployment scenarios of M2M in the prior art:                case 1: an application dedicated node is connected to an infrastructure node by using a reference point X;        case 2: an application dedicated node is connected to an infrastructure nodeinfrastructure node by using a middle node;        case 3: an application service nodeapplication service node is connected to an infrastructure nodeinfrastructure node by using a middle node; and        case 4: an application service nodeapplication service node is connected to an infrastructure node by using a reference point Y.        
Each application dedicated node includes at least one application entity (Application Entity, AE), each application service node includes at least one application entity and at least one common services entity (Common Services Entity CSE), and each middle node includes at least one application entity and at least one common services entity (Common Services Entity CSE).
In the prior art, all application service node/middle node common services entities synchronize data to a data management and storage unit DMR of an infrastructure node common services entity for storage.
Referring to FIG. 4, FIG. 4 is an implementation flowchart of data invoking defined by the existing oneM2M, which is described in detail as follows:
When requesting data of an application service node/middle node common services entity, an AE or a CSE needs to send a request to an infrastructure node common services entity that the application service node/middle node common services entity registers with.
The infrastructure node common services entity queries the request for a state of the application service node/middle node common services entity.
If the state of the application service node/middle node common services entity is an online state, the infrastructure node common services entity delivers the request, and the application service node/middle node common services entity returns requested data in a reply message.
If the state of the application service node/middle node common services entity is an offline state, the infrastructure node common services entity that the application service node/middle node common services entity registers with reserves the request until the request expires, and when the request expires, returns a reply message (failure).
Therefore, in an existing M2M data invoking solution, it needs to be determined, by using an infrastructure node common services entity, that a state of a service node/middle node common services entity is an online state, and then data invoking is performed in the service node/middle node common services entity, and when the state of the service node/middle node common services entity is an offline state, the service node/middle node common services entity cannot invoke data, thereby increasing difficulty of data invoking. In addition, for invoking primary data, there are many command requests between an application node and the middle node. Therefore, byte overheads of signaling exchange between the application node and the middle node are increased, a time taken for data querying and a time taken for data invoking are increased, and data querying efficiency and data invoking efficiency are reduced.